Do 10th, 12th or BTech performance matters for the GATE interviews?

In general they won’t look at your past performances at the time of interviews. They sometimes specify a limit (of 60% etc.) for the interview calls. However your GATE score, conceptual understanding and the way of approaching a problem is what matters by far. However when number of applications are more, then your BE/BTech performance may be considered for short listing for the interview which also depends on Institute’s policy.